The Aspen Cancer Conference, a series of annual scientific meetings, was begun in 1985. The 2001 Conference will be the sixteenth in the series that emphasizes the mechanisms and relationships between toxicity and carcinogenesis and the identification of novel strategies in cancer prevention, diagnosis, and therapy. The Conference organizers recognize that new paradigms are needed to explain that an increasing number of non-mutagenic agents result in carcinogenesis, that cell injury and death, repair, and inflammation are constant companions of cancer development, and that what has been termed "tumor promotion" is a very complex issue. The purpose of these meetings continues to be the assembly of a group of leading scientists working in a wide range of disciplines representing industry, academia, and government, including regulatory agencies, to confer formally and informally on current concepts and aspects of research which transcend the normal boundaries. The unique assembly of these various groups has resulted in stimulated productive discussion leading to fruitful collaborations between scientific groups who do not typically interact. The Aspen Cancer Conference format is designed to encourage ample interaction among participants with twenty minute presentations followed by twenty minutes of discussion in the morning and early afternoon, lunch immediately following whereby discussions continue, and afternoon leisure periods where these interactions have historically continued. The introduction of the Young Investigator Program several years ago has introduced graduate students, medical students, veterinary students, post-doctoral fellows and young faculty into this interactive, informal program. These Young Investigators present posters and discuss, in a relaxed setting, their scientific findings with many of the leaders in their respective fields of study. The informal setting at the Gant Conference Center in Aspen, Colorado and the limited number of participants the Center will accommodate contribute significantly to the successfully interaction of these various scientists. With a maximum of eighty-five participants, greater than fifty percent of whom are newcomers each year, this valuable interaction will successfully continue. During recent years, emphasis has focused increasingly on the molecular aspects of toxicity and carcinogenesis, and the relationship between the two as they relate to human risk. The Sixteenth Aspen Cancer Conference in 2001 will address the following: Chromosomal Dynamics; Cellular Immortality - Stem Cells and Senescense; biomarkers of Cancer; Emerging Technology; Nuclear Import and Export; Rational Cancer Therapy; Experimental Models of Carcinogenesis; and Cellular Stress. The 2001 Conference will include a keynote address on "Apoptosis" to be presented by a prominent scientist, Dr. Stanley Korsmeyer, Harvard University Medical School.